This research investigated the adsorption of Cr(VI) using HNO 3 0,01 M-activated rice straw in a ... more This research investigated the adsorption of Cr(VI) using HNO 3 0,01 M-activated rice straw in a batch system. Some parameters such as pH, initial Cr(VI) concentration, and contact times were examined. The optimum conditions were achieved at the pH 3, initial Cr(VI) concentration 800 mg/L in 15 min with adsorption capacity 60.204 mg/g. It was found that the adsorption of Cr(VI) onto activated rice straw was followed the Freundlich isotherm model (R 2 = 0.9957) and pseudo-second-order model (R 2 = 0.9995) indicating that adsorption chemically occurred and multilayer. Whereas the thermodynamic study revealed that Cr(VI) adsorption onto activated rice straw was exothermic (ΔH° =-8.658 kJ/mol) non-spontaneous reaction (ΔG° = positive) with liquid/solid interface disorder (ΔS° =-65,297 J/mol). The physicochemical characterization of the bioadsorbent showed a wavenumber shifting of some functional groups. The percentage of Cr(VI) in bioadsorbent increased and the surface morphology of the bioadsorbent was smoother after adsorption occurred. Thus, this locally abundant rice straw could be used as a bioadsorbent for Cr(VI) removal.
Students as young generation and agent of change are required to be always active in academic and... more Students as young generation and agent of change are required to be always active in academic and non-academic activities; therefore in the process, they will encounter various obstacles and obstacles. Not infrequently it makes them experience stress. The fact that students often do not know the situation that they are experiencing stress. So there is a need for a system to detect students stress levels to reduce the adverse impacts. With the development of Backpropagation method as a guided learning method combined using Depression Anxiety and Stress Scale 42 (DASS 42) as a scale to identify stress levels in students based on emotional, physical, and behavioural variables. It is expected to be a reference in helping students to detect the level of stress they are experiencing. Also, the use of Backpropagation method is used to see the level of accuracy of data in the system.
This research investigated the adsorption of Cr(VI) using HNO 3 0,01 M-activated rice straw in a ... more This research investigated the adsorption of Cr(VI) using HNO 3 0,01 M-activated rice straw in a batch system. Some parameters such as pH, initial Cr(VI) concentration, and contact times were examined. The optimum conditions were achieved at the pH 3, initial Cr(VI) concentration 800 mg/L in 15 min with adsorption capacity 60.204 mg/g. It was found that the adsorption of Cr(VI) onto activated rice straw was followed the Freundlich isotherm model (R 2 = 0.9957) and pseudo-second-order model (R 2 = 0.9995) indicating that adsorption chemically occurred and multilayer. Whereas the thermodynamic study revealed that Cr(VI) adsorption onto activated rice straw was exothermic (ΔH° =-8.658 kJ/mol) non-spontaneous reaction (ΔG° = positive) with liquid/solid interface disorder (ΔS° =-65,297 J/mol). The physicochemical characterization of the bioadsorbent showed a wavenumber shifting of some functional groups. The percentage of Cr(VI) in bioadsorbent increased and the surface morphology of the bioadsorbent was smoother after adsorption occurred. Thus, this locally abundant rice straw could be used as a bioadsorbent for Cr(VI) removal.
Students as young generation and agent of change are required to be always active in academic and... more Students as young generation and agent of change are required to be always active in academic and non-academic activities; therefore in the process, they will encounter various obstacles and obstacles. Not infrequently it makes them experience stress. The fact that students often do not know the situation that they are experiencing stress. So there is a need for a system to detect students stress levels to reduce the adverse impacts. With the development of Backpropagation method as a guided learning method combined using Depression Anxiety and Stress Scale 42 (DASS 42) as a scale to identify stress levels in students based on emotional, physical, and behavioural variables. It is expected to be a reference in helping students to detect the level of stress they are experiencing. Also, the use of Backpropagation method is used to see the level of accuracy of data in the system.
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